Method of rolling balls



Fehn 3Q 4 I F. M. CANDA METHOD of' ROLLING BALL's .Filed April 25. 1924 .3 Sheetsrjheet 2 Jig@ b--w--w-J 2 Patented F eb. 3, i925.

UNITED .,srrrvApr Es FEBnrivAnn Mona canne, or NEW YORK, N. Y.

mnfriron orv ROLLING BALLS.

Application filed April 25,1924. Serial No. 708,990.

T 0 @ZZ whom tmag/ concern.'

Be it known @that FERDINAND Mona" CANDA, a :citizen of the United States, re siding` at New York city,in the countyof New York and State of New York, have in-p ventedv cert-am new and useful Improvements in Methods of Rolling Balls, of which the following is a specification. "My inventionl rela-tes to a method. of forming metal balls for use especially inL grinding or pulverizing machines.

` v In ball rolling machines usually employed,

an annular groove. Again, if the metal .of

the rod-blank is very hot, the' metal has a tendency to spin, with the result that a central cavity is formed in the ball.

The object of my invention is to provide y an improved method of rolling balls from rod-blanks which will overcome the defects of prior methods above specified and pro-y duce balls having solid cores and substair tially free from surface irregularities, suoli as grooves, creases and other defects.

In the following detailed description I shall refer to the accompanyinof drawings, in which Figure l is a vert-ical transverse sectional view of a ball rolling machine embodying'my invention; Fig. 2'is a vertical sectional view on the line 2 2 ofFig. l; Fig. 3 is a fragmentary detail view on the line 3 3 of Fig. l; Figs. 4t, 5, 6 and 7 are fragmentary views to illustrate the various stages in the formation of the balls as viewed respectively on the lines 4, 5 5, 6 6, andj7 7 of Fig. l; Fig. 8 is an illustrative view to show the partially formed balls in the blank as it is about to emerge from the upper roll; Fig. 9 is an illustrative view showing the blank just after it has entered the second pass between the lower roll and its shoe; and Fig. 10 is an illustrative view showing the finished ball as it is about to emerge from the second pass.

In rolling balls from rods, it is evident that the rods must be smaller in dia-meter thank the diameter of the balls. Tov accomplish the proper finishing` and perfectingfof the balls near the endA of` the rolling operation, the material from which-the `ball-is rolled should approximate very-closelyy to the diameter of thefinished balll andxneces= sarily thegrooves of the roll andthe `shoe must be confined to asemi-circular shape.

I have found that I can eliminate the causes which have heretofore resulted'inthe imperfections in the finished balls andY can pro#v duce much more perfect balls yby `providing a preliminary or roughing pass in which the rod is formed into aconnected series of ball'` elements roughly approximating the ball shape and then subjecting-this: shapedv connected series `of ball elements to the finishing operation between a secondrollfand shoe. I am thereby enabled to employ grooves of an entirely different shape Linfthe roughing pass from those lof* the vfinishingpass Moreover-as the rod is grooved about two-thirds of t-he way 'through in the preliminary pass, less space is-required between the roll andthe shoe in the finishing pass and the progress through the `latter lmay-.-

therefore be made more Igradualv which contributes to a greater accuracy vand perfection in the finished product.;

The grooved rolls l()y and 12 of the upper and lower passes respectively are carried by shafts 14 and l5 which are suitably driven and are geared to rotate in opposite Kd-irections. In themethodsfof rolling spherical balls heretofore employedthe rodv or `bar from which the balls are formed, is subjected: throughout the entire roll-ing operat-ion to the action of grooves that are substantially semiscircular with the resulting defects and imperfections in 4the finished balls above pointed out.

I have found that I can compact the metal and maintain it solid throughout, free from internal flaws when it is forced to flow into the grooves as the ribs cut into the metal, by so shaping thel grooves in the roll l0 and shoe 16 of the preliminary or roughing pass that the sides of the grooves exert pressures toward the center of the ball'element. To this end I make the grooves V-shape with the apex cut off or iattened so that the pass is substantially hexagonal, as shown in Fig. 4. It will be seen that as the ribs cut or bite into the hot metal rod or bar 20, the displaced metal which flows up into the grooves is constantly pressed toward the center of the ball element 2Oa by the inclined sides of the grooves. This prevents any tendency of the metal to spin and maintains the metal solid throughout.

As the metal continues to How into the grooves under the impelling action of the entering ribs, there is a tendency to cause the ball elements to become spool shape with a central annular groove which is diicult to remove in the subsequentrolling and which has heretofore caused imperfections in the linished balls. To obviate this difficulty I so proportion the grooves that thelat central portion bears against the central part of the ball-element while the metal is still flowing into the groove and also position the oblique sides of the groove within the circumference which will be assumed by vthe rod or bar has been cut about two-thirds of the way through so that the ball elements are connected into a longitudinal series by short core parts E2()c as indicated in Fig. 6. Inasmuch as the met-al fills the groove as it nears the end of the roughing pass the center and sides of the groove of the roll exert a kneading action upon the met-al tending to push a surface ridge around the ball element and consequently there will be a slight crease 20e in the ball elements as they roll over the transfer slide 23 between the two passes. `When the blank enters the second pass the oppositely rotating roll l2 will force the metal of this crease back and smooth it out completely.

The grooves of the finishing roll l2 and coacting shoe 18 are approximately semicircular in contour as indicated in Figs. 6 and 7. Inasmuch as most of the cutting act-ion has taken place in the roughing pass and the ball elements approximate their spherical shape, the initial space between the finishing roll l2 and its shoe 18 is only sufficient to receive shaped series of ball element-s and the variation throughout the second pass may be very gradual. After the balls have seperated from each other in the latter part of the finishing pass they are still subjected to the smoothing action of the grooves in which they then tit closely. This is an important improvement in ball rolling machines and contributes materially to the excellence of the iinished balls.

I claim l. rIhe method of forming met-al balls, which comprises axially rolling a heated metal bar and grooving it into a longitudinal series of connected elements angular in section, and subjecting said connected series of elements while still hot to a second rolling operation which transforms said elements into separate spherical bodies.

2. The method of forming metal balls, which comprises axially rolling a heated rod or bar, and grooving it into a connected series of elements of cylindrical frustro-coni-i cal configuration, compressing said elements upon a diameter perpendicular `to and oblique to the axis of said series of elements to compact the saine, and subjecting said series while still hot to a second rolling operation which separates the elements and molds them into spherical shape.

3. The method of forming metal balls which comprises axially rolling a heated metal bar and grooving it into a connected series of elements of oppositely directed conical conformation united at their ends, while maintaining the entire peripheral surface of the metal under centripetal compression and subjecting the metal while still hot to a second axial rolling operation which transforms said series of connected elements into a corresponding number of separate spherical bodies.

In testimony whereof I affix my signature.

FERDINAND MORA CANDA. 

